PICO-THAI Scooter Rider
Number of posts : 43 Location : Chiang Mai , Thailand Points : 5300 Registration date : 2010-07-26
| Subject: Question to motor expert( title edited ) Wed Sep 01, 2010 7:09 am | |
| Cosmic_jumper and I had many exchanges over the HiT clutch. I don't have the luxury to try different spring combinations. Taking off the sidecar is a major undertaking. Now after the experience of Tim I'm ready. But one perhaps crucial question came to my mind=
How much torque, if that is the correct word, do you need to pull off 1200lbs on a very steep hill? Why 2500 rpm? The Hit can be tuned so it locks at 2500. Which I thought is ideal for going slow on very steep rubble roads. Suddenly it occurred to me that 2500 may be good enough to keep the vehicle moving but is also enough rpm power to pull the bike from standstill ? Is there a rule of thumb how much power has to come to the wheel in order to move 1200lbs plus factor x for the extra load/ hill.
Perhaps the locking of the Hit should be set at higher than 2500 rpm. It would be rather awkward to have 125cc Honda Waves 2 cute Thai girls plus children ( reality) overtaking my spacecraft ( by Thai standards) I hope my layman's word make some sense.
Pico
Last edited by PICO-THAI on Thu Sep 02, 2010 9:02 am; edited 1 time in total |
|
Cosmic_Jumper Site Admin
Number of posts : 4415 Age : 81 Location : damn near Philadelphia, PA Points : 10745 Registration date : 2009-06-12
| Subject: Re: Question to motor expert( title edited ) Wed Sep 01, 2010 11:02 pm | |
| I'm going to go out on a limb here; all things being equal, if the HiT Clutch (or any centrifical clutch) is set up to engage at X rpm, adding a heavier load would result in the clutch to slip more --until the inertia is overcome.
That the HiT Clutch is engineered to lock up at Y rpm makes me think that one of two things will happen. One, the clutch will continue to slip somewhat. Or two, the clutch will try to engage (lock), then release, then lock again i.e. the clutch will chatter. If that's the case the clutch is actually trying to get the scoot to wheelie --but given the weight of the scoot, sidecar & load, that will never happen.
Sorry I can be more reassuring, but I'm not an engineer, and your sidecar outfit and road conditions are so rare that it's difficult to imagine solutions.
FWIW; When sidecar outfits are added to geared motorcycles the chain sprockets are usually changed too to lower the gear ratios.
You seem to be 'between a rock and a hard place'. The only thing you can do is go with your best guess. Light Clutch and light Pillow springs work best for my set up.
Last edited by Cosmic_Jumper on Thu Sep 02, 2010 10:06 am; edited 1 time in total |
|
PICO-THAI Scooter Rider
Number of posts : 43 Location : Chiang Mai , Thailand Points : 5300 Registration date : 2010-07-26
| Subject: Re: Question to motor expert( title edited ) Wed Sep 01, 2010 11:15 pm | |
| Thanks Tim, question remains are 2500 rpm enough to pull 1200lbs plus factor x ( steep incline) |
|
Cosmic_Jumper Site Admin
Number of posts : 4415 Age : 81 Location : damn near Philadelphia, PA Points : 10745 Registration date : 2009-06-12
| Subject: Re: Question to motor expert( title edited ) Thu Sep 02, 2010 10:31 am | |
| - PICO-THAI wrote:
- ...question remains are 2500 rpm enough to pull 1200lbs plus factor x ( steep incline)
I'd say that 2500 rpm will certainly start 1200 lbs to move. Most certainly the rpm's will have to increase to get the mass moving faster --and even increase more so in order to move that mass up an incline Assuming that you've ridden that incline before, the HiT Clutch will perform better than your experience using the OEM clutch. i.e. If it worked before it will work better next time. Also don't forget, at 2500 rpm's you are (effectively) just coming off of idle rpm's. You've still got a ways to go before you hit peak Torque and peak HP rpm. With the clutch engaging at that rpm you are much closer to that T/HP range than you'd be if using the OEM clutch. The engine still has 'work' to do before it can get the mass moving and make use of that T/HP range though. Hope I'm not confusing things with my seat-of-the-pants engineering explanations. Tim |
|
dspevack Silver Wing Guru
Number of posts : 2008 Age : 59 Location : Miami, FL Points : 8211 Registration date : 2008-12-27
| Subject: Re: Question to motor expert( title edited ) Thu Sep 02, 2010 10:44 am | |
| Also understand that while the engine puts out 50 hp, you only get about 37 at the rear wheel. Other mods, such as an exhaust change and power commander can add about 5-6 horsepower to what you can use. |
|